1. Field of the Invention
The present invention relates to X-ray masks and the like, and more particularly to an X-ray mark wherein the magnification property can be varied.
2. Description of the Prior Art
U.S. Pat. No. 4,037,111, issued Jul. 19, 1977 to Coquin et al, entitled MASK STRUCTURES FOR X-RAY LITHOGRAPHY, describes various techniques and metallization systems for minimizing the establishment of stresses which cause distortion in X-ray masks.
U.S. Pat. No. 4,384,919, issued May 24, 1983 to Casey, entitled METHOD OF MAKING X-RAY MASKS, discloses an X-ray mask made by forming a thin polymide membrane on a silicon wafer substrate which is then back-etched to form a mask supporting ring of the substrate.
U.S. Pat. No. 4,634,643, issued Jan. 6, 1987 to Suzuki, entitled X-RAY MASK AND METHOD OF MANUFACTURING THE SAME, describes a mask for X-ray exposure composed of an X-ray absorbing layer of tungsten having a desired pattern, a membrane transparent to X-ray and supporting the X-ray absorbing layer, a frame member reinforcing and supporting the membrane at the periphery thereof and films of titanium and/or nickel provided between the membrane and the X-ray absorbing layer. The mask makes it possible to obtain an accurate replication of extremely fine patterns and the desired pattern of the mask can be prepared by the direct dry etching of the X-ray absorbing layer using a resist pattern as the etching mask.